Make International Street Language a real enum, wire up validation

index.ts

@@ -59,7 +59,8 @@ export type { CoordinateLicense, MatchInfo } from "./src/us_street/Candidate.js"
 export type { Geolocation } from "./src/us_autocomplete_pro/Lookup.js";
 export type { AutocompleteSource } from "./src/us_autocomplete/Lookup.js";
 export type { ReverseGeoSource } from "./src/us_reverse_geo/Lookup.js";
-export type { Language, Geocode } from "./src/international_street/Lookup.js";
+export type { Geocode } from "./src/international_street/Lookup.js";
+export { LanguageMode } from "./src/international_street/Lookup.js";
 
 export {
 	Batch,

src/international_street/Client.ts

@@ -4,7 +4,7 @@ import Candidate, { RawIntlStreetCandidate } from "./Candidate.js";
 import buildInputData from "../util/buildInputData.js";
 import apiToSDKKeyMap from "../util/apiToSDKKeyMap.js";
 import { Sender, Response } from "../types.js";
-import Lookup from "./Lookup.js";
+import Lookup, { resolveLanguageMode } from "./Lookup.js";
 
 const keyTranslationFormat = apiToSDKKeyMap.internationalStreet;
 
@@ -19,10 +19,14 @@ export default class Client {
 		if (typeof lookup === "undefined") throw new UndefinedLookupError();
 
 		lookup.ensureEnoughInfo();
+		lookup.ensureValidData();
 
 		const request = new Request();
 		request.parameters = buildInputData(lookup, keyTranslationFormat);
 
+		const resolvedLanguage = resolveLanguageMode(lookup.language);
+		if (resolvedLanguage !== undefined) request.parameters["language"] = resolvedLanguage;
+
 		return new Promise((resolve, reject) => {
 			this.sender
 				.send(request)

src/international_street/Lookup.ts

@@ -1,7 +1,11 @@
 import Candidate from "./Candidate.js";
 import { UnprocessableEntityError } from "../Errors.js";
 
-export type Language = "native" | "latin" | (string & {});
+export enum LanguageMode {
+	Native = "native",
+	Latin = "latin",
+}
+
 export type Geocode = "true" | (string & {});
 
 const messages = {
@@ -24,6 +28,22 @@ function fieldIsSet(field: string | undefined): boolean {
 	return !fieldIsMissing(field);
 }
 
+// Resolves a LanguageMode member or a raw value (eg. from untyped JS callers) into a LanguageMode,
+// matching "native"/"latin" regardless of case. Returns undefined for unset/empty input.
+export function resolveLanguageMode(
+	value: LanguageMode | string | undefined,
+): LanguageMode | undefined {
+	if (!fieldIsSet(value)) return undefined;
+
+	const match = Object.values(LanguageMode).find(
+		(mode) => mode.toLowerCase() === String(value).toLowerCase(),
+	);
+
+	if (!match) throw new UnprocessableEntityError(messages.invalidLanguage);
+
+	return match;
+}
+
 export default class Lookup {
 	result: Candidate[];
 	country: string | undefined;
@@ -37,7 +57,7 @@ export default class Lookup {
 	administrativeArea: string | undefined;
 	postalCode: string | undefined;
 	geocode: Geocode | undefined;
-	language: Language | undefined;
+	language: LanguageMode | undefined;
 	inputId: string | undefined;
 	customParameters: Record<string, string>;
 
@@ -77,19 +97,13 @@ export default class Lookup {
 	}
 
 	ensureValidData(): boolean {
-		const languageIsSetIncorrectly = () => {
-			const isLanguage = (language: string) => this.language!.toLowerCase() === language;
-
-			return fieldIsSet(this.language) && !(isLanguage("latin") || isLanguage("native"));
-		};
-
 		const geocodeIsSetIncorrectly = () => {
 			return fieldIsSet(this.geocode) && this.geocode!.toLowerCase() !== "true";
 		};
 
 		if (geocodeIsSetIncorrectly()) throw new UnprocessableEntityError(messages.badGeocode);
 
-		if (languageIsSetIncorrectly()) throw new UnprocessableEntityError(messages.invalidLanguage);
+		resolveLanguageMode(this.language);
 
 		return true;
 	}

tests/international_street/test_Client.ts

@@ -1,6 +1,6 @@
 import { expect } from "chai";
 import Client from "../../src/international_street/Client.js";
-import Lookup from "../../src/international_street/Lookup.js";
+import Lookup, { LanguageMode } from "../../src/international_street/Lookup.js";
 import Candidate from "../../src/international_street/Candidate.js";
 import errors from "../../src/Errors.js";
 import { MockSender, MockSenderWithResponse } from "../fixtures/mock_senders.js";
@@ -45,8 +45,8 @@ describe("An International Street client", function () {
 		lookup.locality = "h";
 		lookup.administrativeArea = "i";
 		lookup.postalCode = "j";
-		lookup.geocode = "k";
-		lookup.language = "l";
+		lookup.geocode = "true";
+		lookup.language = LanguageMode.Latin;
 		let expectedParameters = {
 			country: "a",
 			freeform: "b",
@@ -58,15 +58,37 @@ describe("An International Street client", function () {
 			locality: "h",
 			administrative_area: "i",
 			postal_code: "j",
-			geocode: "k",
-			language: "l",
+			geocode: "true",
+			language: "latin",
 		};
 
 		client.send(lookup);
 
 		expect(mockSender.request.parameters).to.deep.equal(expectedParameters);
 	});
 
+	it("normalizes a mixed-case language value before sending.", function () {
+		let mockSender = new MockSender();
+		let client = new Client(mockSender);
+		let lookup = new Lookup("CA", "123 Main St");
+		lookup.language = "Latin" as LanguageMode;
+
+		client.send(lookup);
+
+		expect(mockSender.request.parameters["language"]).to.equal("latin");
+	});
+
+	it("does not mutate the original language value when normalizing.", function () {
+		let mockSender = new MockSender();
+		let client = new Client(mockSender);
+		let lookup = new Lookup("CA", "123 Main St");
+		lookup.language = "Latin" as LanguageMode;
+
+		client.send(lookup);
+
+		expect(lookup.language).to.equal("Latin");
+	});
+
 	it("attaches a match candidate from a response to a lookup.", function () {
 		const expectedMockPayload = [{ address1: "A" }];
 		let mockSender = new MockSenderWithResponse(expectedMockPayload);

tests/international_street/test_Lookup.ts

@@ -1,5 +1,5 @@
 import { expect } from "chai";
-import Lookup from "../../src/international_street/Lookup.js";
+import Lookup, { LanguageMode } from "../../src/international_street/Lookup.js";
 import errors from "../../src/Errors.js";
 
 describe("An International Street lookup", function () {
@@ -35,7 +35,7 @@ describe("An International Street lookup", function () {
 
 	it("rejects lookups with an invalid language.", function () {
 		let lookup = new Lookup();
-		lookup.language = "Rubberduckian";
+		lookup.language = "Rubberduckian" as LanguageMode;
 
 		ensureValidationThrows(lookup.ensureValidData, messages.invalidLanguage);
 	});
@@ -52,16 +52,23 @@ describe("An International Street lookup", function () {
 
 	it("accepts lookups with a valid language.", function () {
 		let lookup1 = new Lookup();
-		lookup1.language = "latin";
+		lookup1.language = LanguageMode.Latin;
 
 		expect(lookup1.ensureValidData()).to.equal(true);
 
 		let lookup2 = new Lookup();
-		lookup2.language = "native";
+		lookup2.language = LanguageMode.Native;
 
 		expect(lookup2.ensureValidData()).to.equal(true);
 	});
 
+	it("accepts lookups with a mixed-case language value.", function () {
+		let lookup = new Lookup();
+		lookup.language = "Latin" as LanguageMode;
+
+		expect(lookup.ensureValidData()).to.equal(true);
+	});
+
 	function ensureValidationThrows(callback: any, message: any) {
 		let expectedError = new errors.UnprocessableEntityError(message);